Optical film, multilayer optical film including same, and method for producing optical film

Provided are: an optical Elm that has a good appearance, small in-plane retardation Re, and large thickness-direction retardation Rth; and a method for producing such an optical film. Also provided is a multilayer optical film that uses the optical film, that exhibits little change in retardation as a result of wavelength, and that has small retardation at low wavelengths. The optical film is obtained by sandwiching a melted resin between a first cooling roll comprising an elastic metal roll and a second cooling roll comprising a non-elastic metal roll and molding said melted resin. The optical film has a good appearance, the absolute value of the in-plane retardation Re thereof is 10 nm or less, and the thickness-direction retardation Rth thereof is 40 nm or more.